| Superior thoracic aperture | |
|---|---|
 The thorax from in front. (Superior thoracic aperture visible at top.) | |
 Superior thoracic aperture seen from above | |
| Details | |
| Identifiers | |
| Latin | apertura thoracis superior |
| TA98 | A02.3.04.003 |
| TA2 | 1098 |
| FMA | 7566 |
| Anatomical terminology | |
Thesuperior thoracic aperture, also known as thethoracic outlet, orthoracic inlet refers to the opening at the top of thethoracic cavity.[1] It is also clinically referred to as the thoracic outlet, in the case ofthoracic outlet syndrome. A lower thoracic opening is theinferior thoracic aperture.
The superior thoracic aperture is essentially a hole surrounded by a bony ring, through which several vital structures pass. It is bounded by: the firstthoracic vertebra (T1)posteriorly; the first pair ofribslaterally, forming lateral C-shaped curves posterior to anterior; and thecostal cartilage of the first rib and the superior border of themanubriumanteriorly.
The adult thoracic outlet is around 6.5 cm antero-posteriorly and 11 cm transversely. Because of the obliquity of the first pair of ribs, the aperture slopes antero-inferiorly.
Theclavicle articulates with the manubrium to form the anterior border of the thoracic outlet. Above the superior thoracic outlet is the root of theneck, and the superiormediastinum is inferiorly related. Thebrachial plexus is a superolateral relation of the thoracic outlet. The brachial plexus emerges between theanterior andmiddlescalene muscles, superior to the first rib, and passesobliquely and inferiorly, underneath theclavicle, into the shoulder and then the arm. Impingement of theplexus in the region of the scalenes, ribs, and clavicles is responsible forthoracic outlet syndrome.
Structures that pass through the thoracic inlet include:
This is not an exhaustive list. There are several other minor, but important, vessels and nerves passing through, and an abnormally largethyroid gland may extend inferiorly through the thoracic inlet into the superior mediastinum.
The oesophagus lies against the body of the T1 vertebra, separated from it by theprevertebral fascia, and the trachea lies in front of the oesophagus, in the midline, and may touch the manubrium. The apices of thelungs lie to either side of the oesophagus and trachea, and is separated from them by the other vessels and nerves listed above. Furthermore, they extend slightly superior past the level of the inlet (e.g. the horizontal plane of the first rib).
